Caulobacter crescentus undergoes programmed developmental changes during its cell division cycle, giving rise to two progeny cells,a stalked cell and a motile swarmer cell. Stalked cells adhere to surfaces via the adhesive holdfast, which is found at the tip of the stalk. This holdfast is made in part of a complex polysaccharide containing N-acetylglucosamine (NAG). Since Caulobacter cells can attach to a wide variety of surfaces, the holdfast must be rather more complex than simply NAG. A genetic screen will be used to identify new genes and components involved in the adhesion process. Using various surfaces with different chemical properties in the screen will allow for the identification of genes that are required for adhesion to various types of surfaces. The identity of the mutated genes will be determined. This may identify unknown adhesins or genes required for the synthesis of non-protein adhesive components. In addition, the role of the S-layer and of the S-layer secretion machinery in attachment to surfaces will be tested. Understanding the mechanisms by which bacteria attach to surfaces is important since adhesion to host cells is the first step in any infection.